In the evolution of automotive design, great importance has recently been placed on automotive safety and ergonomics. Modern automobiles are provided with many safety systems to protect both the vehicle itself and its passengers, in the event of a collision. Among such safety systems is the supplemental passenger restraint system for the front seat occupants of the vehicle. This system, oftentimes referred to as an air bag system, is provided in the hub of the steering wheel for the vehicle driver and occasionally, at the right-hand end of the vehicle's instrument panel for the front seat passenger.
In the case of the driver's side supplemental restraint system, the hub of the steering wheel houses an air bag, a rapidly combustible material which when burned, gives off gases which inflate the bag and an ignition system for initiating the combustion. The hub is covered by a soft, frangible, flexible cover which tears open under the force of air bag inflation, thereby allowing the bag to fill the area of the passenger compartment between the driver and the steering wheel as the bag inflates. The flexibility of the cover contributes to the frangibility thereof, provides a soft shock absorbing surface to reduce the risk of injury during minor incidents in which the air bag does not deploy, and provides an aesthetically pleasing extension of the colors and textures employed in other parts of the vehicle's passenger compartment.
One of the primary goals of modern ergonomic vehicle design is to provide controls which are conveniently accessible to the driver with a minimum of diversion of the drivers attention from the road. Since the vehicle's accessories are, for the most part, manually actuatable and operable, accessories such as horns, cruise controls and the like are conveniently operable from the steering wheel itself. Historically, horn buttons (switches) were positioned at the center of the steering wheel and studies have shown that drivers who are not completely familiar with the operation of a vehicle will instinctively reach for the center of the steering wheel when they wish to operate the horn. However, prior art horn buttons have not generally been conducive for use with steering wheels having flexible air bag covers. Thus, automotive interior designers have been forced to move horn buttons to the spokes of the steering wheel and, in some cases, to stalks extending outwardly from the steering column. Both locations have been found to be more inconvenient than the center of the steering wheel from the standpoint of the driver.
Recently, conventional horn switches have been mounted in vehicle steering wheel hubs beneath air bag modules containing the bag, a gas generator and an ignitor so that when it is desired to actuate the horn, the driver depresses the entire air bag module. Typically, a plurality of horn switches are connected in parallel to the vehicle's wiring within the hub of the steering wheel, below the air bag module such that actuation of any single switch will activate the horn. Heretofore, it has been the practice to employ stamped metal or wire conductors to connect such horn switches to the vehicle's wiring by such prior art connectors as crimp or screw-type connectors. Such arrangements exhibit a number of significant shortcomings. For example, use of individual wires and/or metal stampings requires substantial hand labor during vehicle assembly operations and, therefore, contributes significantly to the cost of steering wheel assembly. Moreover, such stamped metal connectors and individual wires are also subject to damage from overlying components in the supplemental restraint system when the steering wheel is assembled. In fact, it is oftentimes necessary to employ wire retention clips to position the wires so as not to be so damaged, to employ shields to protect the wires from such damage, both of which add to the bulk and complexity of the steering wheel assembly and contribute further to the manufacturing costs thereof.
Moreover, with the prior art connection techniques mentioned hereinabove, there is significant risk of assembly error. That is, right-hand and left-hand conductor stampings risk being inadvertently reversed in vehicle assembly operations, often resulting in inoperability of the electrical system within the steering wheel or damage to the horn switch connections during subsequent assembly operations. Quality control testing of such systems is also inconvenient in that it must be performed within the vehicle as the vehicle undergoes further assembly.
Accordingly, an improved scheme for making electrical connections to vehicle accessory switches such as horn switches and the like in a steering wheel hub beneath an air bag module, characterized by simplicity and reliability of structure, economy of manufacture, and ease of assembly and testing is desirable.